For a Carnival Cruise in 2026, final boarding (the "All Aboard" time) is typically 60 to 90 minutes before the ship's scheduled departure. If your ship is scheduled to depart at 4:00 PM, you must be on board and have completed the check-in process by 2:30 PM or 3:00 PM at the latest. Carnival is extremely strict with this requirement because the ship's manifest must be finalized and submitted to U.S. Customs and Border Protection before the gangway can be pulled up. A grounded reality: if you arrive after the gangway is up, you will be denied boarding without a refund, and you will be responsible for traveling to the next port of call at your own expense. A supportive peer tip: when you complete your Online Check-in, you will select a specific Port Arrival Time (e.g., 12:30 PM). You should aim to arrive at the terminal 30–60 minutes before that window to account for traffic and security lines. This ensures you are among the first to board, giving you a chance to enjoy the lido deck lunch while the "last-minute" rush is still stuck in the terminal.